PHNOM PENH - THE Khmer Rouge prison chief told Cambodia's UN-backed war crimes trial on Tuesday that he was 'shocked' when confronted with his bloody past and has prayed annually for forgiveness.

'When I arrived at S-21, I was shocked for the numerous things that happened there. I saw the victims or the survivors - three of them - who stood before me. What happened in the past came back into my mind,' Duch said.

The 66-year-old was describing his visit with court investigators last year to the former prison, which now serves as a genocide museum, so that he could re-enact his crimes. Duch's defence team proceeded to show a short video of the visit, in which he attempts to speak but begins to sob uncontrollably, removes his glasses and is comforted by his lawyer.

'I made a speech for the souls of those who died. This is something that I can never forget, the trip to Choeung Ek (the so-called killing field where prisoners were killed) and S-21 in Phnom Penh,' Duch said.

He told the court he became consumed with sorrow after fleeing the prison in the face of Vietnam's 1979 invasion of Cambodia, and began to make an annual prayer offering.

'First I asked forgiveness to my parents, then I asked forgiveness from all my teachers, then I asked forgiveness to the victims of all the crimes,' Duch said.

He then asked judges for permission to make a statement to the daughter of one of Tuol Sleng's victims who was sitting in court. However trial chamber president Nil Nonn denied the request, telling him he would only be allowed to use testimony to speak to victims near the end of proceedings.

Earlier in the day, Duch told the court he was twice incriminated in written confessions by prisoners interrogated at his jail, and both times he left the text for his superiors to see in trust that his loyalty would save him.

'I did not make any changes to it because if I did, people would notice that I deleted my name because I did not want to be implicated,' Duch said. -- AFP